<?php

namespace think\db\builder;

use think\db\Builder;

/**
 * mysql数据库驱动
 */
class Mysql extends Builder
{
  protected $updateSql = 'UPDATE %TABLE% %JOIN% SET %SET% %WHERE% %ORDER%%LIMIT% %LOCK%%COMMENT%';

  /**
   * 字段和表名处理
   * @access protected
   * @param string $key
   * @param array  $options
   * @return string
   */
  protected function parseKey($key, $options = [])
  {
    $key = trim($key);
    if (strpos($key, '$.') && false === strpos($key, '(')) {
      // JSON字段支持
      list($field, $name) = explode('$.', $key);
      $key                = 'json_extract(' . $field . ', \'$.' . $name . '\')';
    } elseif (strpos($key, '.') && !preg_match('/[,\'\"\(\)`\s]/', $key)) {
      list($table, $key) = explode('.', $key, 2);
      if (isset($options['alias'][$table])) {
        $table = $options['alias'][$table];
      }
    }
    if (!preg_match('/[,\'\"\*\(\)`.\s]/', $key)) {
      $key = '`' . $key . '`';
    }
    if (isset($table)) {
      $key = '`' . $table . '`.' . $key;
    }
    return $key;
  }

  /**
   * 随机排序
   * @access protected
   * @return string
   */
  protected function parseRand()
  {
    return 'rand()';
  }
}
